How does the author use foreshadowing in The Wings of the Dove?

In Book Third: Chapters V - VI, lives are beginning to mesh. It becomes obvious that Kate, Merton, Maud, Milly and Susan will all come to know one another in London. Milly's motives appear to be quite innocent in contacting Merton, as do Susan's motives in calling upon Maud. Yet, there is important foreshadowing in these two chapters as well. Milly is young and without heirs, and one must suspect Susan's motives for her self imposed purpose of directing such a wealthy young lady's life. On the other hand, there is a sense that Milly may have an illness that is more far-reaching than her few days of illness in New York. James has succeeded in interjecting some mystery for the reader, and thus, the motivation to continue reading.